1. Field of the Invention
This invention relates generally to coffee grinders and, more specifically, to electrically powered grinders that employ rapidly rotating grinding discs.
2. Discussion of the Prior Art
Electrical coffee grinders of the type that have grinding wheels that operate a high speed are well known in art. Reference may be made to co-pending PCT application serial number PCT/US00/11379 filed Apr. 28, 2000 and entitled xe2x80x9cCoffee Grinder with Removable Ingredient Hopper and Methodxe2x80x9d, which is hereby incorporated by reference for some of the details of such grinders. Briefly, they include a hopper containing the coffee beans and having an outlet with an electrically controlled gate. When the outlet gate is opened, the coffee beans pass through the outlet and into a grinding chamber within which are contained a set of intermeshing grinding discs or wheels that are driven in rotation by an electrical motor. The ground coffee then passes out of the grinding chamber and through an outlet chute and into a suitable container or into a brew basket with a filter paper to hold the ground coffee. The discs are preferably made of ceramic but others are made of stainless steel.
A problem with such grinders is often small particles of the ground coffee known as chaff, chaff fines, or fines, fly out of the chute and misses the filter within the brew basket or other container. It escapes from the top of the brew basket even though pressed against the grinder housing. The chaff flies through the air and eventually lands on the outside surfaces of the grinder housing, the brew basket, the counter tops and the floors and wall in the vicinity of the grinder. Although most of the ground coffee makes it into the filter paper within the brew basket, over time the grounds that do not make it into the filter accumulate and must be cleaned up. In addition to making a mess, the loose coffee grounds are wasted.
It is believed by the present inventor that this problem is caused or exasperated by the grinding action of the grinding discs with the ground coffee causing a positive static charge being built up on the individual fine particles of ground coffee, or chaff. As a result of the static charge being all of the same polarity, the charged chaff particles are repelled from one another, from the coffee grounds that are in the brew basket and generally from any other positively charged surfaces. It is believed that this is why there is not a smooth flow of the ground coffee including the chaff in a contained stream from the outlet chute without dispersion of the chaff particle outside of the stream.
In accordance with the present invention, the aforementioned problem of loose chaff is overcome by artificially creating a source of negative ions through which the positively charged chaff must pass to neutralize the chaff before passing from the outlet chute.
This objective is achieved in part by providing a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs, and an outlet chute for passing the ground coffee out of the grinding chamber, with a chaff dispersion reducing apparatus having means for artificially creating negatively charged ions within the housing and means for passing the negatively charged ions into contact with chaff produced during the grinding of the coffee beans to neutralize the chaff before leaving the housing. Preferably, the ion creating means creates ions in the outlet chute while the emitter is mounted in communication with the interior of the outlet chute adjacent an open, outlet end of the outlet chute.
Preferably, the generating means is a negative ion generator that functions to ionize ambient atoms of air to give them a negative charge. The negative ion generator has an emitter, and means for producing an electrical charge on the emitter having a voltage sufficiently high to emit large quantities of electrons to negatively ionize the air. The producing means includes a D.C. power supply for producing a low current, high voltage D.C. voltage on the emitter connected with a source of A.C. power. Preferably, the voltage is on the order of 8400-volts. A ion generator power supply located within the housing and outside of the interior produces the high voltage and a power lead extending to the emitter is mounted in communication with the interior of the outlet chute.
The objective of the invention is also obtained in part by providing in a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs, and an outlet chute for passing the ground coffee out of the grinding chamber with a method of reducing chaff dispersion and to enhance the controlled flow of chaff out of the outlet chute by performing the steps of artificially creating negatively charged ions within the housing, and passing the chaff into contact with the negatively charged ions before the chaff passes out of the outlet chute to electrically neutralize the chaff.
The objective is also obtained by providing a coffee grinder having housing containing a hopper for storage of coffee beans to be ground, a grinding chamber with a set of intermeshing grinding discs, a hopper outlet, gate for selectively passing coffee beans from the hopper to the grinding chamber to be ground by the set of intermeshing grinding discs with a chaff dispersion reducing apparatus having means for artificially creating negatively charged ions, and means for passing the ground coffee and chaff through the negatively charged ions to neutralize the chaff.
Preferably, the coffee grinder includes an outlet chute for passing ground coffee from the grinding chamber to a brew basket with a outlet pipe for passing the ground coffee from the grinding chamber to the brew basket, and an insulating collar surrounding the metal outlet pipe and in which said creating means creates negatively charged ions within the collar and beneath an outlet end of the outlet pipe. The insulated collar has a bottom with a downwardly facing annular groove surrounding the outlet pipe and in which the creating means creates negatively charged ions within the annular groove. The emitter extends from an emitter body contained within a mounting hole in the collar into the groove to create ions within the groove and beneath a bottom outlet end of the outlet pipe. The grinder has means for mounting an open top of a brew basket against a bottom of the collar and the ions are created beneath the bottom of the outlet pipe and within the brew basket, the brew basket retarding dispersion of the ions to areas through which the chaff does not pass.